Dual mode circuit breaker withdrawal mechanism



P 23, 1969 cs. A. WILSON 3,469,043

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w N w v X a @v MNN NW\ w N a QQ mQ kbm mm I IWH N sum Amway United States Patent 3,469,043 DUAL MODE CIRCUIT BREAKER WITHDRAWAL MECHANISM George A. Wilson, Media, Pa., assignor, by mesne assignments, to I-T-E Imperial Corporation, Philadelphia, Pa., a corporation of Delaware Filed July 19, 1967, Ser. No. 654,594 Int. Cl. H01h 9/20, 33/46 US. Cl. 200-50 17 Claims ABSTRACT OF THE DISCLOSURE Racking mechanism for moving a circuit breaker within its cubicle between connected, test, disconnect, and out positions, which includes provisions for both electrical and manual operation. Manual operation can move the breaker through all of its positions while electrical operation can move the breaker only between its connected and test position. Apparatus is provided to condition electrically actuated movement of the circuit breaker in an indicated direction only upon the breakers being in the one of its two possible positions from which it is intended to be moved.

This invention relates to withdrawal mechanism for circuit breakers, and more particularly to withdrawal or racking mechanism which includes both manual and electrical means for moving a circuit breaker between its various positions within a circuit breaker cubicle.

In most uses of large circuit breakers, the breaker is housed within a suitably dimensioned cubicle. For obvious safety reasons, the breaker main and secondary conductors extend from the rear of the circuit breaker whereby they may be electrically connected to associated main and secondary external conductors which pass through the rear wall of the cubicle. To fulfill basic operating, testing and servicing requirements, it is generally required that the circuit breaker be movable between three positions and in addition thereto, the circuit breaker must be capable of being quickly and easily withdrawn from the cubicle.

The three positions correspond to a connected position in which the breaker main and secondary conductors are electrically connected to their respective external main and secondary conductors; a test" position in which the circuit breaker main conductors are electrically isolated from their respective external main conductors, while the breaker secondary conductors, or selected ones thereof, remain electrically connected to their respective external secondary conductors; and the disconnected condition in which both the breaker main and secondary conductors are electrically isolated from their respective external main and secondary conductors. As noted above, a final requirement for the breaker, although not electrical in nature, is that the breaker may be easily withdrawn from its cubicle.

Present means for establishing the various circuit breaker positions and for withdrawing the' breaker from its cubicle comprise racking apparatus interconnected between the circuit breaker and its cubicle for manually moving the circuit breaker with its main and secondary conductors away from their associated external main and secondary conductors whereby the necessary clearance is established between the breaker conductors and external conductors, respectively. Thus in the connected position the breaker occupies its most rearward position within its cubicle such that the breaker main and secondary conductors are electrically connected to their repective external conductors. Manual operation of the racking mechanism moves the circuit breaker forward within its cubicle such that the main breaker conductors, but not the secondary conductors, are of sufiicient distance from their associated external main conductors so that electrical clearance is established therebetween. The breaker now occupies the test position. Further operation of the racking mechanism again moves the breaker forward in its cubicle such that the breaker secondary conductors are of sufiicient distance from their respective secondary conductors to establish electrical clearance therebetween. The breaker is now in its fully disconnected position. Further operation of the racking mechanism disconnects the racking mechanism from the cubicle such that the breaker may be withdrawn therefrom.

As noted, the racking mechanism described above is manually operable, that is, requires the presence of an operator to physically rotate a crank which, in turn, moves the breaker within its cubicle. However, in certain instances where the breaker installation is in an inconvenient location, it is desirable and indeed sometimes necessary that the breaker be able to be moved from its connected to its test position from a control point physically remote from the breaker installation.

The instant invention provides the solution to this problem by providing a circuit breaker racking mechanism which includes both manually operable apparatus for moving the circuit breaker between its various cubicle positions and additionally includes electrically energizable apparatus for permitting the circuit breaker to be moved between its connected and test positions from a location remote from the breaker and its cubicle. Furthermore, and in accordance with the instant invention, there is provided means for conditioning electrically actuated movement upon the circuit breakers being initially in the position from which it is to be moved.

As a particularly advantageous feature of the instant invention, various safety features are provided which cooperate with the basic racking mechanism. Thus, as a. first safety feature, the withdrawal or racking mechanism cannot be operated either electrically or manually when the circuit breaker contacts are closed. Secondly, the circuit breaker contacts cannot be' closed unless the breaker is in either the connected, test, or disconnected positions. Third, the withdrawal mechanism automatically stops and locks at each of the four positions whether electrically or manually operated. Finally, the above noted mechanism permits the application of manual control of the racking mechanism at any point in the breaker travel in or out, in the event of control power failure.

Accordingly, it is an object of the instant invention to provide circuit breaker racking mechanism which includes both manually operable apparatus for moving the circuit breaker within its cubicle and additionally includes electrically energizable apparatus for permitting the circuit breaker to be moved between its various cubicle positions from a location remote from the breaker and its cubicle.

Another object of the instant invention is to provide such a racking mechanism which includes means for conditioning electrically actuated movement upon the circuit breakers being in that one of its two possible positions from which it is to be moved.

Still another object of the instant invention is to provide such a racking mechanism which includes a host of safety features cooperating-therewith.

Yet another object of the instant invention is to provide such a racking mechanism which automatically stops and locks at each of the various circuit breaker positions.

Still another object of the instant invention is to provide such a circuit breaker racking mechanism which prevents the circuit breaker contacts from being closed unless the breaker is in the connected, test, disconnected positions.

Another object of the instant invention is to provide such a withdrawal mechanism which cannot be' operated either electrically or manually when the circuit breaker contacts are closed.

Other objects and a fuller understanding of the instant invention may be had by referring to the following description and drawings, in which:

FIGURE 1 is a somewhat schematic showing of a circuit breaker in which the instant invention may find application, showing the breaker in a fully connected position within an associated cubicle;

FIGURES 2A, 2B and 2C show the circuit breaker of FIGURE 1 in the test, disconnect, and out positions, respectively;

FIGURE 3 is a perspective view of the racking mechanism of the instant invention;

FIGURE 4 is a front view of the racking mechanism of FIGURE 3;

FIGURE 5 is a side view of the racking mechanism of FIGURE 3;

FIGURE 6 is a top view of the racking mechanism of FIGURE 3;

FIGURE 7 is a view of a portion of the racking mechanism of FIGURE 3;

{FIGURE 8 is a view of a portion of the racking mechanism of FIGURE 3; and

FIGURES 9A and 9B show portions of the racking mechanism of FIGURE 3 and the circuitry therefor.

Referring specifically to FIGURE 1, there is shown a circuit breaker 10 housed within a circuit breaker cubicle or housing identified as 12. As is conventional in the art, the door 14 of cubicle 12 may be opened to permit the circuit breaker to be withdrawn by means of wheels 16. Breaker 10 conventionally includes three pairs of rearwardly extending main conductors 18 and 20 (only one pair being shown) which are to be electrically connected and disconnected by main disconnect contact pairs 22 and 24 (only one pair being shown) to three pairs of external main conductors 28 and 30 (only one pair being shown) which pass through the rear wall 32 of cubicle 12.

Similarly, breaker 10 includes multiple pairs of secondary conductors 34 and 36 (only one pair being shown) which are to be electrically connected and disconnected by means of secondary disconnect contacts 38 and 40 to multiple pairs of external secondary conductors 44 and 46 which pass through the rear wall 32 of cubicle 12. The breaker main and secondary conductors 18, 20 and 34, 36, respectively, are spaced apart and secured in place by an insulating support molding generally indicated at 48.

The opposite end of conductor 18 is electrically connected to a substantially U-shaped stationary contact structure 50 which cooperates with movable contact 52, pivoted to rotate about pivot point 54 on the opposite end of conductor 20. Movable contact 52 is schematically connected by links 56 and 58 to a jackshaft 60. Rotation of jackshaft 60 is in response to energization of either a time delayed tripping device (not shown) calibrated for overload conditions, or an instantaneous'tripping device (not shown) calibrated for high fault current, rotates movable contact 52 between its engaged and tripped position.

As is conventional, stationary contact structure 50 and movable contact 52 are each provided with main and auxiliary contacts 62, 64 and 66, 68, respectively, arranged so that main contacts 62 and 66 separate before auxiliary contacts 64 and 68. Thus an arc being drawn between contacts 64 and 68 may be readily transferred to are runners 70 and 72 which extend upwardly into an arc chute 74 wherein the rising arc may be quickly extinguished.

It is to be understood that although FIGURE 1 shows only one phase, the circuit breaker shown in FIGURE 1 can be a multi-phase breaker wherein each phase is provided with similar apparatus to provide circuit interruption and are extinguishment therein. Furthermore, it is to be understood that although the instant invention will be described with respect to a multi-pole breaker, the concept of the instant invention may be equally applied to a circuit breaker comprising one or more poles.

As indicated previously, the circuit breaker 10 must be capable of assuming three positions and an out position. To this end there is provided a pair of racking arms 76 on opposite sides of the circuit breaker with such racking arms being fixedly secured on a shaft 78 and rotatable therewith in response to rotation of the shaft 78 effectuated by either manual or electrical means, as will be explained in greater detail. The racking arms 76 each carry an Outstanding roller 80 which is received within a channel defined by two upstanding brackets 82 and 84 secured by suitable means on the inner surfaces of the side walls of the cubicle (only side wall 86 is visible in FIGURE 1).

Thus it will be appreciated that rotation of the racking arm 76 counterclockwise in FIGURE 1 to the position shown in FIGURE 2A will move the circuit breaker 10 from the fully connected position of FIGURE 1 to the test position of FIGURE 2A in which the main conductors 18 and 20 are electrically isolated from the main external conductors 28 and 30, but the secondary conductors 34 and 36 are still in engagement with the relatively long external secondary conductors 44 and 46 by way of the secondary disconnect contacts 38 and 40. Further rotation of the racking arm 76 on the shaft 78 to the position of FIGURE 2B will move the circuit breaker to the fully disconnected position in which both the main conductors 18 and 20 and the secondary conductors 34 and 36 will be electrically disconnected from their respective external main and secondary conductors.

Finally, referring to FIGURE 2C, it will be appreciated that the raised portion 84' of bracket 84 is shorter than the raised portion 82' of bracket 82. Thus when the racking arm 76 is rotated from the position of FIGURE 2B to the position of FIGURE 2C, the roller 80 falls below the raised surface 84 of the bracket 84 such that the breaker now occupies the out position in the sense that the racking arm 76 is disconnected from the track defined by the brackets 82 and 84. Thus, after opening the door 14, one can physically pull the breaker 10 out of the cubicle 12.

To insert the breaker 10 in the cubicle 12, the steps are the reverse. That is, the breaker is inserted into the cubicle manually, until the roller 80 of the racking arm 76 engages the raised surface 82 of the longer bracket 82. Then the crank arm 76 is rotated on the shaft 78 clockwise (in a manner to be further explained) through the various positions illustrated in FIGURES 2B, 2A and 1 such that the breaker moves from the out position of FIGURE 2C through the fully disconnected position, the test position, and to the fully connected position of FIG- URE 1.

As noted previously, the instant invention provides both electrical and manual means for effecting movement of the breaker between the various positions illustrated in FIGURES 1-2C and thus, and in accordance with the explanation given immediately above, must therefore provide both manual and electrical means for rotating the racking arm 76 (that is, the shaft 78) in both the clockwise and counterclockwise direction.

MANUAL OPERATION Referring to FIGURES 3, 4 and 5, it may be seen that manual racking may be accomplished by inserting a removable crank 88 in a keyed opening 90 provided on the front of a drive shaft 92. Drive shaft 92 carries a worm 94 which meshes with a worm gear 96 fixedly secured to the shaft 78. Thus in its simplest form, rotation of the drive shaft 92 causes the rotation of racking arms 76 via the worm 94, gear 96 and shaft 78.

Fixedly secured to the shaft 78 is a timing disc 98 having a plurality of indexing notches 100, 102 and 104 which correspond to the fully connected, test and disconnected positions, respectively. A lever assembly 108 is pivotally mounted at 110 and biased by spring 112 (FIG- URE 4) such that one end 114 thereof is continually biased toward the timing disc 98. If in fact one of the indexing notches such as 100, shown in FIGURE 3, confronts the one end 114 of the lever assembly 108, then the biasing spring 112 urges the one end 114 into such notch. It will be appreciated that when the end 114 of the lever assembly 108 is in a notch such as 100, a roller 120 on the end 114 will be seated in a cut-out cam surface 118 provided in a cam 116, rigidly secured to drive shaft 92 and it will not be possible to rack the circuit breaker between its various positions since shaft 92, to which the worm gear 96 is secured, cannot be rotated. Thus, in order to rotate the shaft 78 via the drive shaft 92, it is necessary to propel the roller 120 of the lever assembly 108 out of the cut-out notch 118 in cam 116.

However, it may be further appreciated that before the lever assembly 108 can be rotated clockwise (in FIG URE 3), a latch 126 secured on a locking shaft 128 must be removed from the path of movement of a roller 130 carried between the plates 122 and 124 of the lever assembly 108. However, the locking shaft 128 may be rotated clockwise as by the handle 132 only if certain predetermined conditions have been fulfilled.

Specifically, and referring to FIGURES 3 and 4, so long as a blocking screw 134 is in blocking relationship with respect to a lever 136 secured to the unlocking shaft 128, such shaft 128 cannot be rotated clockwise in FIG- URE 3 to unlock the latch 126 from the roller 130. Fur thermore, blocking screw 134 is fixed for rotation on a shaft 138 which carries at one end a lever 140, one end 144 (FIGURE 6) of which rests on a lever 142 which is secured to and rotatable with the jackshaft 60, which, as noted previously, controls the opening of the circuit breaker contact such as 52 shown in FIGURE 1. End 144 of the lever 140 is attached to the lever 142 by suitable link 146 and thereby follows the movement of lever 142. As indicated by the notations closed and open, the solid line position of lever 142 corresponds to the closed circuit condition of the contact 52 of FIGURE 1 while the phantom showing of the lever 142 indicates the circuit breaker contact 52 in its open circuit condition. It will be appreciated therefore that when the jackshaft 60 has been rotated clockwise in the direction of arrow 148, in FIGURE 3, from its closed circuit to its open circuit condition, crank lever 140 will rotate in the direction of arrow 150 which will rotate shaft 138 in the same direction which, in turn, will move the blocking screw 134 out of engagement with the lever 136 which is secured on the unlocking shaft 128. Thus only when the circuit breaker contacts are open, can the unlocking shaft 128 be rotated to unlock the lever 126 from the roller 130 of the lever assembly 108 to permit movement of the circuit breaker 10. A complete description of manual operation of the racking mechanism to move the circuit breaker from the connected position of FIGURE 1 to the test position of FIGURE 2A will now be presented.

Assuming that the circuit breaker contacts are open, such that the blocking screw 134 occupies the position indicated as 134' in FIGURE 4, the operator grasps the handle 132 and rotates the unlocking shaft 128 clockwise, as viewed in FIGURES 3 and 4, to remove the latch 126 from the roller 130. The removable crank 88 is then rotated in a counterclockwise direction, as viewed in FIGURE 3, such the cut-out cam surface 118 of the cam 116 pushes the roller 120 out to the left, as seen in FIGURE 4, to rotate the lever assembly 108 clockwise about the fixed pivot 110 such that end 114 is pulled out of the indexing notch 100. The cam 116 and the worm 94 continue to rotate and the worm gear 96 and the timing disc 98 are rotated in a counterclockwise direction as viewed in FIGURE 3. This causes rotation of the racking arm 76 in a counterclockwise direction from the position shown in FIGURE 1 toward the position shown in FIGURE 2A. It should be noted that when the cam 116 has rotated 360 such that the roller 120 should fall back into the notch 118, the indexing notch in the timing disc 98 is no longer confronting the end 114, such that the end 114 is biased by the spring 112 against the surface of the timing disc 98 and the roller cannot enter the notch 118.

The lever assembly 108 is thus held in a clockwise direction against the bias of spring 112 by the timing disc 98 until the racking arm 76 has moved the breaker to the test position of FIGURE 2A, at which time the indexing notch 102 is aligned with the end 114 of the lever assembly 108 and the lever assembly can then rotate counterclockwise as viewed in FIGURE 3. The latch 126 would then reset behind the latch roller 130 as shown. Any further rotation of the crank 88 is then blocked until the unlocking shaft 128 has again been deliberately ro tated by the operator. The same procedure is repeated in progressing on out to the disconnect and out positions, and vice versa when progressing from the out to the fully connected positions.

As one further safety feature, it may be pointed out that whenever the locking shaft 128 has been rotated clockwise as viewed in FIGURE 3, such that the latch 126 is in non-blocking relationship with respect to the roller 130, lever end 137 is rotated clockwise to rotate a lever assembly 139 counterclockwise, as viewed in FIG- URE 3, to rotate a shaft 141 and a lever 143 counterclockwise in the direction of arrow 145. As indicated in block diagram form, the breaker closing mechanism 147 (that mechanism which closes the contacts 52 of FIGURE 1 after there has been an interruption) is held inoperative whenever the lever 143 has been rotated to the phantom line position 143' by the shaft 141. Thus the circuit breaker closing mechanism can never be operated when the circuit breaker is moving between its various positions.

ELECTRICAL OPERATING MEANS As noted previously, the instant invention provides that the circuit breaker can be moved between its various positions manually, and electrically (between its connect and test positions) from a point remote from the circuit breaker installation. To provide the basic movement of the breaker electrically, a reversible electric motor 150 is provided on the output shaft 152 of which is provided a gear 154 which meshes with a gear 156 positioned on the drive shaft 92. An electrically operated clutch 158 is provided to connect the gear 156 to the drive shaft 92, in a manner to be further explained.

Electrical operation from the connect to the test position may be explained as follows. The out remote control pushbutton 160 of FIGURE 9B is depressed which completes a circuit path from a source 162 through a conductive member 164 (FIGURE 9A) joining terminals 166 and 168, in a manner to be further described, to energize the motor 150 and a solenoid 170, best seen in FIGURE 7. It may be pointed out that the source 162 emanates externally of the circuit breaker cubicle and is carried to the breaker through the secondary conductors 44, 46 and breaker secondaries 34, 36. Therefore, it will be appreciated that movement of the circuit breaker by electrical means may only be accomplished between the connected and test positions and vice versa since when the circuit breaker is in its disconnected or out positions, there will be no control power supplied to the breaker. It may be appreciated, however, that if desired, other sources might be provided if it is desired to electrically work the breaker between the test and disconnect positions.

Turning to FIGURE 7, it will be seen that the armature 172 of the solenoid is linked to a lever 176 by a pin 178 and that the lever 176 is normally biased in a clockwise direction about a fixed pivot point 180 by a spring 182. One end of the lever 176 carries a screw 184 while the other end thereof is linked by pin 186 to a vertically movable rod 190.

Unlocking shaft 128 carries a lever 192 (see also FIG- URE 3) which is normally biased by a spring 194 toward the solid line position shown in FIGURE 7. However, energization of the solenoid 170 which, as noted previously, is caused by the depression of the remote out switch 160 of FIGURE 9B, draws the armature 172 downward into engagement with the core 174 which in turn, rotates the lever 176 in a counterclockwise direction as viewed in FIGURE 7 which lifts rod 190 to cause the shoulder 196 thereof to rotate the unlocking lever 192 to the dotted line position 192' shown in FIGURE 7. This in turn rotates the unlocking shaft 128 which, in turn, removes the latch 126 from the locking relationship with respect to the roller 130 of the lever assembly 108 which, as previously explained, mrmits the circuit breaker to be moved. The rod 190 is held up by a screwhead 238 on latch bracket 236 which seats under a notch 240 in the rod 190. Latch bracket 236 is biased clockwise by spring 237.

As the lever 176 is rotated counterclockwise in FIG- URE 7, the screw 184 comes down and closes a switch 198 to energize the electric clutch 158 which connects the rotating gear 156 (the motor 150 has been previously energized) with the drive shaft 92. As explained previously, the rotating drive shaft 92 propels roller 120 of lever assembly 108 from the cut-out notch 118, and through the worm 94 rotates the shaft 78 and racking arm 76 which moves the breaker toward the test position. Movement continues until the breaker reaches the test position, at which time the motor and clutch are disconnected, in a manner which will become apparent.

As noted previously, the motor 150 is a reversible motor, with the direction of rotation of the output shaft 152 gov erning the direction of rotation of the drive shaft 92 and hence the direction of breaker travel. As will be explained immediately below, the direction of rotation of the motor is predetermined by the previous making of suitable contacts in a rotary switch 200, seen in FIGURE 8 and schematically shown in FIGURES 3 and 9A. Rotary switch 200 is part of a mechanism, to be described immediately below, which continually conditions the operation of the electrical racking operation upon the circuit breakers being in the position from which it is to be moved.

SYNCHRONIZING MECHANISM As best seen in FIGURES 3 and 4, the plates 122 and 124 of lever assembly 108 include elongated slots 202 and 204 which loosely carry a pin 206 which is carried at one end of a link 208 (shown as a phantom line only in FIG- URE 3), the other end of which is connected by a pin 210 to one end of a lever 212 pivoted on the lever arm assembly 108 at 214. A biasing spring 216 urges the small lever 212 clockwise, as viewed in FIGURE 4, such that the nose 218 thereof is normally held against the surface of timing disc 98. It will be appreciated that as the timing disc 98 rotates counterclockwise, as viewed in FIGURE 3, an opening 220 therein approaches the nose 218 of the lever 212 such that the spring 216 urges the nose 218 into the opening 220. The clockwise rotation of lever 212 lifts the link 208 and with it the pin 206 from a lower vertical position, shown in FIGURE 3, to an upper vertical position illustrated at 206-4, FIGURE 4.

Thus it will be appreciated that the pin 206 will actually occupy four distinct positions as the circuit breaker is moved from its connected to its test position. Initially the pin 206 occupies the position shown in FIGURE 3 at the bottom of the slots 202 and 204 in the plates 122 and 124. This position is identified as 2061 in FIGURE 4. Subsequently, upon rotation of the drive shaft 92, the cam 116 engages the roller 120 supported between the plates 122 and 124 to rotate lever assembly 108 clockwise as viewed in FIGURE 4. Thus the pin 206 moves from the position shown as 206-1 to 206-2 and remains in 8 this position as the timing disc 98 rotates counterclockwise as viewed in FIGURE 3.

Subsequently the opening 220 of the timing disc 98 confronts the nose 218 of the lever 212; the lever 212 is now free to rotate clockwise under the influence of spring 216 to lift link 208 and with it the pin 206 from the position shown at 206-2 to the position indicated as 206-3 in FIGURE 4. Finally, when the circuit breaker has reached the test position, the end 114 of the lever assembly 108 enters the indexing notch 102 and the entire lever assembly 108 is rotated counterclockwise, as viewed in FIGURE 4, such that the pin 206 now moves from its position 2063 to its final position 2064.

It is the movement of this pin 206 which controls the contacts in rotary switch 200 to synchronize the reversing motor with any previous movement of the circuit breaker by either electrical or mechanical means. Specifically, rotary switch 200 includes a shaft 222, one end of which carries the conductive member 164 and the opposite end of which carries the lever 224 externally of the switch housing. When the moving breaker reaches the test position, the lever assembly is received by indexing notch 102 and the pin 206, in moving between the third and fourth position (see FIGURE 9A), strikes the lever 224 which, in turn, rotates the shaft 222 to change the position of the conductive member 164 from that shown in solid in FIGURE 9A to that shown at 164' in phantom in FIGURE 9A. (Note that the pin positions 2061 through 206-4 of FIGURE 9A are reversed from the pin positions identified in FIGURE 4, since, as indicated, and as clearly seen in FIGURES 3 and 6, that portion of the shaft 222 of the rotary switch 200 which carries the lever 224 faces the rear of the circuit breaker.) Movement of the conductive member 164 to the position 164' electrically connects terminals 226 and 228 which, as indicated in FIGURE 9B, will reverse the application of source 162 to the motor 150 when the in pushbutton 230 is later depressed. Thus if the breaker had been manually racked to the test position of FIGURE 2A, depressing the out pushbutton would have no affect since there would be an open circuit across terminals 166 and 168, while depressing the in pushbutton 230 will reverse the direction of rotation of the shaft 152 of motor 150 to reverse the direction of rotation of the drive shaft 92 and cause the circuit breaker to be electrically racked from its test position back to its connected position of FIGURE 1.

If the breaker had been racked from its connected to its test position by the electric motor 150, then as the pin 206 had moved from the position 206-3 to 2064 to rotate the lever 224 and shaft 222, the movement of the conductive member 164 oi the terminal 166 and 168 would also break the circuit to motor 150. Also, as the lever assembly 108 resets in the indexing notch 102 (which has the reason for the pin moving from 206-3 to 2064) a pin 232, seen in FIGURES 3, 6 and 7, carried in the lever assembly 108 strikes an adjusting screw 234 to rotate the latch bracket 236 counterclockwise about the fixed pivot (see FIGURE 7). Rotation of latch bracket 236 counterclockwise removes the upstanding screwhead 238 thereof from the notch 240 in the vertical rod which, under the influence of biasing spring 194 and the latch 192, returns the vertical rod 190 to its solid line position shown in FIGURE 7. This rotates lever 176 clockwise to break switch 198 and de-energize the electric clutch 158 which prevents the stopping motor 150 from having any further influence on the drive shaft 92.

As noted above, when the conductive member 164 of the rotary switch 200 is rotated to electrically connect terminals 226 and 228, then depression of the in pushbutton 230 will reverse the potential applied to motor 150 and initiate opposite rotation of the shaft 152 thereof to physically move the circuit breaker from its test back to its connetced position with all steps of the sequence being exactly the same but reversed. Thus when the circuit breaker approached the fully connected position, the pin 206, in moving from the position 206-2 to 206-1, would rotate the lever 224 and the shaft 222 of the rotary switch 200, to break the motor circuit (if the racking was being accomplished electrically) and at the same time arm the rotary switch for subsequent electrical operation from the connected to the test position in response to the depression of the out pushbutton 160.

It will be appreciated that the reversing lever 212 is actuated as described above by either electrical or manual operation to set up the proper circuit so that the electrical control is never de-synchronized from the manual control.

Thus there has been described racking mechanism for a circuit breaker which provides both electrical and manual capabilities. Furthermore, releasable locking means in the form of latch member 126 in association with the shaft 128 has been provided which will permit racking of the breaker only after a predetermined condition, namely, the opening of the circuit breaker contacts has been fulfilled. Furthermore, releasable positioning means in the form of lever assembly 108 has been provided to cooperate with the releasable locking means and the timing disc to accurately locate and position the circuit breaker once it has reached the exact location of its various positions.

Although there has been described a preferred embodiment of this novel invention, many variations and modifi-cations will now be apparent to those skilled in the art.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. Racking mechanism for moving a circuit breaker relative to a fixed surface between first and second positions, said circuit breaker also being movable to another position, said racking mechanism comprising:

racking arm means secured to said circuit breaker, said racking arm means cooperatively engaging said fixed surface to move said circuit breaker between its first and second positions and between its second and first positions in response to movement of said racking arm means in first and second directions, respectively;

manually operable means linked to said racking arm means for manually effecting movement of said racking arm means in either of its first and second directions; electrically energizable means linked to said racking arm means for electrically effecting movement of said racking arm means in either of its first and second directions; and

means interconnecting said manually operable means and said electrically energizable means for conditioning the operation of said electrically energizable means such that said electrically energizable means, when energized, effecting automatic movement of said racking arm means in its first direction to move said circuit breaker toward its second position, only when said circuit breaker is in its first position, and said electrically energizable means effecting automatic movement of said racking arm means in its second direction to move said circuit breaker toward its first position only when said circuit breaker is in its second position, said energizable means preventing automatic movement of said circuit breaker to said another position.

2. The racking mechanism of claim 1, wherein said racking arm means occupies a first position when said circuit breaker is in its first position and a second position when said circuit breaker is in its second position, and wherein said circuit breaker is further movable relative to said fixed surface between its second position and a third position in response to movement of said racking arm means in its first direction from its second position to a third position, and wherein only said manually operable means is effective to move said racking arm means between its second and third position.

3. The racking mechanism of claim 1, and further including releasable locking means cooperating with said manually operable means and said electrically energizable means for preventing either of said manually operable means or said electrically energizable means from effecting movement of said racking arm means from its first to its second position unless a predetermined condition has been fulfilled.

4. The racking mechanism of claim 3 wherein said circuit breaker includes at least one pair of cooperating contacts capable of assuming engaged and disengaged positions relative to one another, and said predetermined condition is that said cooperating contacts are in their disengaged position.

5. The racking mechanism of claim 4, wherein said circuit breaker includes closing mechanism for moving said cooperating contacts from their disengaged to their engaged position; and further including latch means for preventing operation of said closing mechanism whenever said circuit breaker is moving between its first and second positions.

6. The racking mechanism of claim 1, wherein said means interconnecting said manually operable means and said electrically energizable means includes contact means movable between a first circuit position which primes said electrically energizable means for efiectuating movement of said racking arm means in its first direction, and a second circuit position which primes said electrically energizable means for effectuating movement of said racking arm means in its second direction; said racking arm means being linked to said contact means to move said contact means from its first circuit position to its second circuit position whenever said racking arm means has moved in its first direction to move said circuit breaker to its second position, and to move said contact means from its second circuit position to its first circuit position whenever said racking arm means has moved in its second direction to move said circuit breaker to its first position.

7. The racking mechanism of claim 1, and further including positioning means cooperating with said racking arm means for stopping said circuit breaker once it has reached the exact location of its first and second positions.

8. The racking mechanism of claim 7, and further including releasable locking means cooperating with said positioning means for releasing said positioning means to permit further movement of said circuit breaker.

9. The racking mechanism of claim 8, wherein said circuit breaker includes at least one pair of cooperating contacts capable of assuming engaged and disengaged positions relative to one another, and wherein said releasable locking means is capable. of being operated to release said positioning means only when said contacts are in their disengaged position.

10. The racking mechanism of claim 9, wherein said circuit breaker includes closing mechanism for moving said cooperating contacts from their disengaged to their engaged position; and further including latch means cooperating with said positioning means for preventing operation of said closing mechanism whenever said positioning means is released such that said breaker may be moved between its first and second position.

11. The racking mechanism of claim 8, and further including an indexing disc rotatable with said racking arm means, said indexing disc having first and second indexing notches corresponding to the first and second positions of said circuit breaker, respectively; and said positioning means includes a pivotably rotatable lever assembly, one end of which is biased toward said indexing disc such as to enter one of said indexing notches when said circuit breaker is in one of its first and second positions, the other end of said pivotally rotatable lever assembly being normally blocked from possible movement by said releasable locking means, whereby said lever assembly cannot be rotated to make possible rotation of said indexing disc and racking arm means unless said releasable locking means has been released.

12. The racking mechanism of claim 11, wherein said circuit breaker includes at least one pair of cooperating contacts capable of assuming engaged and disengaged positions relative to one another, and wherein said releasable locking means is capable of being removed from blocking relationship with respect to said other end of said lever assembly to permit retraction of said one end of said lever assembly from said indexing notches of said indexing disc only when said contacts are in their disengaged position.

13. The racking mechanism of claim 12, wherein said releasable locking means can be released manually and electrically.

14. The racking mechanism of claim 11, and further including a common actuating member, wherein said manually operable means and said electrically energizable means cooperate with said common actuating member for efiecting rotation of said racking arm means and said indexing disc so long as said one end of said lever assembly is retracted from said indexing notches; and said common actuating member includes cam means for expelling said one end of said lever assembly from said indexing notches in response to rotation of said common actuating member by either of said manually operable means or electrically energizable means.

15. The racking mechanism of claim 14, wherein said electrically energizable means includes contact means movable between a first circuit position which primes said electrically energizable means for effectuating rotation of said racking arm means in its first direction, and a second circuit position which primes said electrically energizable means for efiectuating rotation of said racking arm means in its second direction; said contact means being moved between its first and second circuit positions in response to the various motions of said lever assembly as said circuit breaker moves between its first and second positions.

16. The racking mechanism of claim 15, wherein said lever assembly includes an elongated slot; and wherein there is further included a pin which is movable between first and second vertical positions within said elongated slot, said lever assembly further including a reversing linkage pivoted thereon which cooperates with said indexing disc to move said pin between its first and second vertical positions as said racking arm means moves said circuit breaker between its first and second position such that said second indexing notch of said indexing disc approaches a confronting relationship wtih respect to said one end of said lever assembly; whereby said pin will move between a first, second, third and fourth position when said circuit breaker is moved between its first and second position; said first position corresponding to a location of said pin when said circuit breaker is in its first position and said one end of said lever assembly is located in said first indexing notch, said second position being said first vertical position when said cam means has expelled said one end of said lever assembly from said first indexing notch; said third position corresponding to said second vertical position, said fourth position corresponding to a location of said pin when said circuit breaker is in its second position and said one end of said lever assembly is located in said second indexing notch; movement of said pin between its third and fourth position changing said contact means from its first to its second circuit position thereby priming said electrically energizable means for effectuating rotation of said racking arm means in its second direction, whereby when energized said electrically energizable means will move said circuit breaker from its second to its first position.

17. The racking mechanism of claim 16, wherein the sequence of said four positions of said pin is reversed when said circuit breaker is being moved from its second position to its first position, and said pin moves said contact means from its second to its first circuit position as said pin moves from. its. second position to its first position, said pin movement occurring during both manual and electrical operation.

- References Cited UNITED STATES PATENTS 3,193,633 77 7/1965 Netzel et al 20050.15

ROBERT K. SCHA'EFER, Primary Examiner M. GINSBURG, Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3469043 Dated September 2:5, I969 Inventorfis') George A. Wilson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, Line 66 after "such" insert:--that-- Column 6, Line 34 change "l43" to:--141 Column 7, Line 46 change "SYNCHRONIZING" tow- CONDITIONING Column 8, Line 15 change "synchronize" to:--condition- GIGNED M SEAL! Anal:

namanmmri m I m M8 flomiasionar o1. ratznta FORM PO-I uscoMM-oc 603764 65 

